Pregnancy is really, really common in all sorts of mythology and folklore. Based on your two choices, I would say look at The Seven Swans, which you may have heard of, and The Silver Hands, which you probably haven't. Also, if you simply need a small child, not necessarily a pregnancy, try The Juniper Tree, which has both a pregnancy, two small children, murder, cannibalism, magic, revenge and (to my sick, twisted mind, at least) a fair amount of very grim humor.